Device for fixing substrate for thin film sputter and method of fixing substrate using the same

ABSTRACT

A device to fix a substrate for a thin film sputter, includes a mask, a mask pressing plate, a magnetic body, and a driving unit. The mask having patterns is positioned under the substrate so as to form the patterns on the substrate. The mask pressing plate is positioned over the substrate and moves toward and contacts a back surface of the substrate at a predetermined pressure. The magnetic body is placed over the mask pressing plate and moves toward the mask pressing plate so as to have the mask adhere closely to the substrate by a magnetic force of the magnetic body. The driving unit applies a driving force to move the magnetic body. Where the mask pressing plate descends, the mask pressing plate adheres closely to the substrate. Thereafter, the magnetic body descends toward the back surface of the substrate which is supported by the mask pressing plate. The mask underneath the substrate adheres closely to a front surface of the substrate by the magnetic force of the magnetic body. Accordingly, since the substrate is multi-step supported, the alignment of the mask underneath the substrate is not dislocated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.2002-30613, filed May 31, 2002, in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device which fixes a substrate, andmore particularly, to a device, which fixes a substrate for a thin filmsputter, having an improved structure so as to uniformly deposit thinfilms on the substrate, and a method of fixing the substrate using thesame.

2. Description of the Related Art

Organic electroluminesence displays are spontaneous luminescence typedisplays, which electrically excite a fluorescent organic compound toemit light. The organic electroluminesence displays have advantages inthat they can be driven at a low voltage and manufactured with a narrowthickness. The organic electroluminesence displays are viewed by many asnext generation displays which can solve many of the disadvantagesassociated with, for example, liquid crystal displays (LCDs), by having,for example, a wide view angle (WVA) and a fast response time.

Where power is supplied, a current flows with the movement of electronsin the organic electroluminescence displays. In other words, in acathode, electrons move to a light-emitting layer via the assistance ofan electron transport layer, while in an anode, holes move to thelight-emitting layer via the assistance of a hole transport layer. Theelectrons and holes in the light-emitting layer made of an organicmaterial create an exciton having a high energy. Here, a drop in energyof the exciton causes light to be emitted. Light of full color can berealized depending on the kind of an organic material of thelight-emitting layer.

Generally, an organic electroluminescence display having theabove-described structure is formed by a vacuum deposition method toform organic thin films, such as an electron transport layer, a holetransport layer, a light-emitting layer, or the like. In this vacuumdeposition method, a substrate, on which organic thin films will beformed, is mounted inside a vacuum chamber in which a pressure iscontrolled to be within a range of 10⁻⁶–10⁻⁷ torr. Next, an organicmaterial contained in a furnace is sublimated so that the organicmaterial is deposited on the substrate. U.S. Pat. Nos. 5,833,823,6,132,575 and 6,251,233B1 disclose such a vaccum deposition method.

FIGS. 1A and 1B show a portion of a conventional sputter which fixes asubstrate so as to form thin films on the substrate. As shown in FIG.1A, a substrate 11 is mounted over a frame 13. A mask 12, which haspredetermined patterns to be formed on the substrate 11, is positionedbetween the substrate 11 and the frame 13. A fixture 100 is disposedover the substrate 11 to support the substrate 11. The fixture 100includes a magnet plate 101 and a rubber magnet 102 which is attachedonto a backside of the magnet plate 101.

The fixture 100 is positioned over the substrate 11 via a robot carrier(not shown) to support the substrate 11, and the mask 12 is alignedunderneath the substrate 11.

As shown in FIG. 1B, the fixture 100 descends to the substrate 11. Then,the mask 12, which is made of a metallic material and is positionedunderneath the substrate 11, is deformed toward the fixture 100 having amagnetic force and adheres closely to the substrate 11.

The rubber magnet 102 of the fixture 100 is placed on a back surface ofthe substrate 11 so as to support the substrate 11. In this manner,where the mask 12 is closely adhered to the substrate 11, a sputteringoperation is performed.

However, where a distance between the mask 12 and the fixture 100 isnarrow, a central portion of the mask 12 ascends first. In this case,while the central portion of the mask 12 may satisfactorily adhereclosely to the substrate 11, both margins of the mask 12 do not properlyadhere closely to the substrate 11.

As a result, patterns are not formed in right positions of the substrate11 and are spread to other portions. Also, where the central portion ofthe mask 12 ascends prior to other portions of the mask 12, as the mask12 adheres closely to the substrate 11, the mask 12 slips underneath thesubstrate 11. Therefore, the substrate 11 may be scratched by the mask12.

To solve these problems, a conventional fixture 200 shown in FIGS. 2Athrough 2C has been suggested. The fixture 200 includes a rubber magnet201 and a mask pressing plate 202 which is adhered onto a lower surfaceof the rubber magnet 201. A process of fixing the substrate 11 using thefixture 200 will be now described.

First, the fixture 200 is transferred over the substrate 11 via a robotcarrier, (not shown) and a mask 12 is aligned underneath the substrate11. Thereafter, as shown in FIG. 2B, the fixture 200 descends while themask 12, which is made of a metallic material and is positionedunderneath the substrate 11, ascends by a magnetic force of the rubbermagnet 201. Here, the mask pressing plate 202 contacts the back surfaceof the substrate 11.

Next, as shown in FIG. 2C, the mask pressing plate 202 may completelypress the substrate 11 so that the mask 12 adheres closely to and isfixed to the substrate 11. Thereafter, a sputtering operation isperformed.

However, it is difficult for the mask 12 to completely adhere closely tothe substrate 11 since a contact surface of a frame 13 with the mask 12has the flatness of about 50 micrometers.

Accordingly, in order to improve a close adhesiveness between thesubstrate 11 and the mask 12, a magnetic force which is stronger than amagnetic force of the rubber magnet 201 has to be used, or a pressingforce has to be increased/strengthened. However, where a magnetic bodyhaving a magnetic force stronger than the magnetic force of the rubbermagnet 201 is used, the mask 12 slips underneath the substrate 11. As aresult, an alignment of the mask 12 underneath the substrate 11 may bedislocated, or a leakage current may flow over a completed product.Furthermore, a method of strengthening an adhesive force between thesubstrate 11 and the mask 12 may crack or scratch the substrate 11.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide adevice to fix a substrate for a thin film sputter by which uniformpatterns can be formed on the substrate, by multi-step supporting thesubstrate in a vacuum deposition process so as to improve the closeadhesion of a mask to the substrate, and a method of fixing thesubstrate using the same.

Additional aspects and advantages of the invention will be set forth inpart in the description which follows and, in part, will be obvious fromthe description, or may be learned by practice of the invention.

To achieve the above and/or other aspects of the present invention,there is provided a device for fixing a substrate with respect to a maskprovided below the substrate, the device comprising a mask pressing bodywhich is positioned over the substrate, and moves toward and contactsthe substrate at a predetermined pressure, a magnetic body which isplaced over the mask pressing plate and moves toward the mask pressingplate so as to adhere the mask to the substrate using a magnetic forceof the magnetic body, and a driving unit which moves the magnetic body.

The device may further comprise guide bars which are connected to themask pressing body and guide units which are provided at respective endsof the guide bars, wherein the guide bars ascend and descend through themagnetic body. The guide bars may slide down through the guide units bytheir own weight so as to have the mask pressing body descend toward theback surface of the substrate.

The device may further comprise elastic bias units installed at theguide bars to apply a set pressure to the mask pressing body.

The mask pressing body may be a nonmagnetic plate.

The magnetic body may include a magnet plate and a rubber magnet whichis attached onto a lower surface of the magnet plate.

To achieve the above and/or other aspects of the present invention,there is provided another device for fixing a substrate with respect toa mask provided below the substrate, the device comprising a maskpressing body which is positioned over the substrate, an elevating unitwhich moves the substrate and the mask toward the mask pressing body soas to have the substrate contact the mask pressing body, a magnetic bodywhich is placed over the mask pressing plate and moves toward the maskpressing plate so as to adhere the mask to the substrate using amagnetic force of the magnetic body, and a driving unit which moves themagnetic body.

To achieve the above and/or other aspects of the present invention,there is provided yet another device for fixing a substrate with respectto a mask provided below the substrate, the device comprising amulti-step fixing unit which contacts the substrate with a non-magneticpart thereof and adheres the mask to the substrate using a magneticforce of a magnetic part thereof, and a driving unit which drives themulti-step fixing unit.

To achieve the above and/or other aspects of the present invention,there is provided a method of fixing a substrate with respect to a maskprovided below the substrate, using a device having a magnetic body, adriver and a mask pressing plate which are provided above the substrate,the method comprising adhering the mask pressing plate to the substrate,allowing the magnetic body to move toward a back surface of thesubstrate which is supported by the mask pressing plate, and adheringthe mask underneath the substrate to a front surface of the substrate byusing a magnetic force of the magnetic body.

The adhering of the mask pressing plate to the substrate comprisesmoving the mask pressing plate towards the back surface of thesubstrate, perpendicular to the magnetic body, so as to adhere the maskpressing plate to the substrate.

The adhering of the mask pressing plate to the substrate comprisesmoving the substrate and the mask underneath the substrate toward afront surface of the mask pressing plate, at the same time, so as toadhere the substrate to the mask pressing plate

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the present invention willbecome apparent and more readily appreciated from the followingdescription of the embodiments, taken in conjunction with theaccompanying of which:

FIG. 1A is a partial view of a conventional device for fixing asubstrate, which is aligned over the substrate;

FIG. 1B is a view illustrating the device shown in FIG. 1A, whichdescends toward the substrate;

FIG. 2A is a partial view of another conventional device for fixing asubstrate, which is aligned over the substrate;

FIG. 2B is a view illustrating the device shown in FIG. 2A, whichdescends toward the substrate;

FIG. 2C is a view illustrating the device shown in FIG. 2B, whichadheres to the substrate;

FIG. 3 is a perspective view of a device for fixing a substrateaccording to an embodiment of the present invention;

FIG. 4 is a cross-sectional view of the device shown in FIG. 3, which isaligned over the substrate;

FIG. 5 is a cross-sectional view of the device shown in FIG. 3, whichdescends toward the substrate;

FIG. 6 is a cross-sectional view of the device shown in FIG. 3, whichadheres closely to the substrate; and

FIG. 7 is a cross-sectional view of a device for fixing a substrateaccording to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below in order to explain thepresent invention by referring to the figures.

FIG. 3 shows a device 300 to fix a substrate for a thin film sputteroperation, according to an embodiment of the present invention. As shownin FIG. 3, the device 300 includes a magnet plate 301. The magnet plate301 is, for example, a metal plate which is made of a magnetic material.A rubber magnet 302 is attached onto a lower surface of the magnet plate301. The rubber magnet 302 is made of, for example, a high elasticmaterial having a strong magnetism.

The magnet plate 301 onto which the rubber magnet 302 is attached issupported by a drive shaft 310. The drive shaft 310 is coupled to adrive motor 320, which supplies power to ascend and descend the driveshaft 310 The drive motor 320 may be a servo motor which allows thedrive shaft 310 to ascend and descend to a predetermined targetdistance.

A mask pressing plate 303, which is made of, for example, a nonmagneticmaterial, is positioned under the rubber magnet 302. The mask pressingplate 303 is supported by guide bars 330. The guide bars 330 passthrough the magnet plate 301 onto which the rubber magnet 302 isattached, so as to ascend and descend perpendicular to the magnet plate301. The guide bars 330 are combined with guide units 340 so as to slideup and down in the guide units 340. The device 300 is installed in avacuum atmosphere, and upper and lower portions of the guide units 340are opened so as to have vacuum smoothly progress through the upper andlower portions of the guide units 340.

A substrate 11 is placed under the mask pressing plate 303. Patternformation portions 11 a are disposed on the substrate 11 to form aplurality of flat panel displays, for example, organicelectroluminescence displays. A mask 12, in which pattern portions 12 aare formed, is installed under the substrate 11 to form patterns, suchas organic thin films, in the respective pattern formation portions 11 acorresponding to the organic electroluminescence displays. The mask 12is fixed by a frame 13.

A method of fixing the substrate 11 using the device 300 having theabove-described structure will be now described with reference to FIGS.3–6.

Referring to FIG. 4, the device 300 is positioned over the substrate 11via a robot carrier (not shown). Next, the mask 12 is correctly alignedunderneath the substrate 11.

As shown in FIG. 5, the mask pressing plate 303 descends toward a backsurface of the substrate 11. The mask pressing plate 303 adheres closelyto the back surface the substrate 11 as the guide bars 330 slide downthrough the guide units 340 by, for example, their own weight. Here,since the magnet plate 301, onto which the rubber plate 302 is attached,does not move, the alignment of the mask 12 underneath the substrate 11is not dislocated by a magnetic force.

On the other hand, the mask pressing plate 303 may not descend while thesubstrate 11 and the mask 12 may ascend via an additional elevating unit(not shown) so as to have the substrate 11 adhere closely to a frontsurface of the mask pressing plate 303.

As described above, the mask pressing plate 303 adheres closely to thesubstrate 11.

As shown in FIG. 6, the magnet plate 301, onto which the rubber plate302 is attached and which is connected to the drive shaft 310, descendsby a driving force of the drive motor 320. The rubber plate 302 contactsa back surface of the mask pressing plate 303. Thus, the mask 12underneath the substrate 11 adheres closely to a lower surface of thesubstrate 11 by a magnetic force of, for example, the magnet plate 301.

Here, the substrate 11 has already been supported by the mask pressingplate 303. Thus, the mask 12 is not dislocated underneath the substrate11. The substrate 11 to which the mask 12 is closely adhered is suppliedwith a pressure, for example, equal to a weight of the mask pressingplate 303. Here, the pressure can be controlled.

FIG. 7 shows a device 300 for fixing a substrate 11 according to anotherembodiment of the present invention. In other words, where a pressure islow, as shown in FIG. 7, elastic bias units 440, for example, springs,are installed at guide bars 430 which support a mask pressing plate 303,so as to apply an additional pressure to the weight of the mask pressingplate 303. In a case where a pressure is high, the mask pressing plate303 may be formed of a material having an appropriate weight to controlthe pressure.

The above-described device to fix a substrate for a thin film sputter,according to the present invention, and the method of fixing thesubstrate using the device have the following non-exclusive advantages.

Since a mask pressing plate and a rubber plate multi-step support asubstrate, a mask is not dislocated underneath the substrate.Furthermore, the mask can be kept from slipping on the substrate, andthus the substrate can be prevented from being scratched.

Although a few embodiments of the present invention have been shown anddescribed, it will be appreciated by those skilled in the art thatchanges may be made in these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined inthe appended claims and their equivalents.

1. A device for fixing a substrate with respect to a mask provided belowthe substrate, the device comprising: a mask pressing plate which ispositioned over the substrate, and moves toward and contacts thesubstrate at a predetermined pressure; a magnetic body which is placedover the mask pressing plate and moves toward the mask pressing plate soas to adhere the mask to the substrate using a magnetic force of themagnetic body; a driving unit which moves the magnetic body; guide barswhich are connected to the mask pressing plate; and guide units whichare provided at respective ends of the guide bars, wherein the guidebars ascend and descend through the magnetic body.
 2. The device ofclaim 1, wherein the guide bars slide down through the guide units bytheir own weight so as to have the mask pressing body descend toward theback surface of the substrate.
 3. The device of claim 2, furthercomprising elastic bias units which are installed at the guide bars toapply a set pressure to the mask pressing plate.
 4. The device of claim1, wherein the mask pressing plate is a nonmagnetic plate.
 5. The deviceof claim 1, wherein the magnetic body comprises a magnet plate and arubber magnet which is attached onto a lower surface of the magnetplate.
 6. The device of claim 1, wherein the driving unit comprises adrive motor and a drive shaft which supports the magnetic body so as toallow the magnetic body to ascend and descend.
 7. The device of claim 1,wherein: the device is provided in a vacuum atmosphere, and the guideunits include openings so as to have vacuum progress therethrough.